In a coming-out party of sorts in Geneva, flashbulbs popped Thursday as the nonprofit Mona Lisa Foundation pulled back the curtain to present what it claims is a predecessor of the world's most famous portrait.

But even experts brought in by the foundation aren't sure just yet.

The claims are certain to rekindle questions about the famed painting in Paris' Louvre Museum and shake up accepted beliefs about the artwork.

The "Isleworth Mona Lisa" features a dark-haired young woman with her arms crossed against a distant backdrop. The foundation says it's no copy but an earlier version of the Louvre masterpiece.